/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.lucene.index;

import org.apache.lucene.util.AttributeSource;

/**
 * This class tracks the number and position / offset parameters of terms
 * being added to the index. The information collected in this class is
 * also used to calculate the normalization factor for a field.
 * 
 * @lucene.experimental
 */
public final class FieldInvertState {
    int position;
    int length;
    int numOverlap;
    int offset;
    int maxTermFrequency;
    int uniqueTermCount;
    float boost;
    AttributeSource attributeSource;

    public FieldInvertState() {
    }

    public FieldInvertState(int position, int length, int numOverlap, int offset, float boost) {
        this.position = position;
        this.length = length;
        this.numOverlap = numOverlap;
        this.offset = offset;
        this.boost = boost;
    }

    /**
     * Re-initialize the state, using this boost value.
     * @param docBoost boost value to use.
     */
    void reset(float docBoost) {
        position = 0;
        length = 0;
        numOverlap = 0;
        offset = 0;
        maxTermFrequency = 0;
        uniqueTermCount = 0;
        boost = docBoost;
        attributeSource = null;
    }

    /**
     * Get the last processed term position.
     * @return the position
     */
    public int getPosition() {
        return position;
    }

    /**
     * Get total number of terms in this field.
     * @return the length
     */
    public int getLength() {
        return length;
    }

    public void setLength(int length) {
        this.length = length;
    }

    /**
     * Get the number of terms with <code>positionIncrement == 0</code>.
     * @return the numOverlap
     */
    public int getNumOverlap() {
        return numOverlap;
    }

    public void setNumOverlap(int numOverlap) {
        this.numOverlap = numOverlap;
    }

    /**
     * Get end offset of the last processed term.
     * @return the offset
     */
    public int getOffset() {
        return offset;
    }

    /**
     * Get boost value. This is the cumulative product of
     * document boost and field boost for all field instances
     * sharing the same field name.
     * @return the boost
     */
    public float getBoost() {
        return boost;
    }

    public void setBoost(float boost) {
        this.boost = boost;
    }

    /**
     * Get the maximum term-frequency encountered for any term in the field.  A
     * field containing "the quick brown fox jumps over the lazy dog" would have
     * a value of 2, because "the" appears twice.
     */
    public int getMaxTermFrequency() {
        return maxTermFrequency;
    }

    /**
     * Return the number of unique terms encountered in this field.
     */
    public int getUniqueTermCount() {
        return uniqueTermCount;
    }

    public AttributeSource getAttributeSource() {
        return attributeSource;
    }
}
